Portable media players to which latest electronic technologies are applied are widely gaining popularity due to a reason that low power consumption can be realized, along with reduction in price and size. In media players in recent years, a small storage medium capable of storing image information with a large amount of information and a compression coding technique are combined. Accordingly, it becomes possible to reproduce various contents.
Also, as devices which are connectable to the media players, not only headphones and earphones but head mounted displays (hereinafter referred to as “HMD”) such as a near-eye display apparatus and the like are also developed so as to correspond flexibly to needs of users. An HMD is a device which is wearable on a user's head and is capable of projecting a video on a retina from the front of a user's eye. By connecting the HMD to a media player, wearing the HMD on head, and further manipulating a manipulating part of the media player, the user can watch a content including images such as a movie and a music clip.    Patent document 1: Japanese Unexamined Patent Application Publication No. H10-133840